Zero Fingerprint Enrollment System for an Electronic Device

ABSTRACT

This application provides techniques, including circuits and designs, which can receive information with respect to fingerprint images, or portions thereof, and which can be incorporated into devices using fingerprint recognition. This application also provides techniques, including devices which perform fingerprint recognition and methods which can be performed by those devices. In one embodiment, techniques can include providing a fingerprint recognition sensor in which one or more portions of each fingerprint can be collected as they are identified, and those portions can be combined into a unified fingerprint template. In this way, collection and enrollment of fingerprints may be simplified for users.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 13/841,287, filed Mar. 15, 2013, and entitled “ZeroFingerprint Enrollment System for an Electronic Device,” which claimsthe benefit under 35 U.S.C. §119(e) to U.S. Provisional PatentApplication No. 61/666,717, filed Jun. 29, 2012, and entitled “ZeroEnrollment,” both of which are incorporated by reference in theirentirety as if fully disclosed herein.

FIELD

This application generally relates to fingerprint sensors.

BACKGROUND

Fingerprint recognition systems generally provide for collection offingerprint information and comparing that information against adatabase of known fingerprints. For example, a set of known fingerprintsfor an authorized user can be collected, and a accessing user can beauthorized by comparing fingerprint information for that accessing useragainst known fingerprint information for that authorized user. Thisgenerally involves collecting fingerprints from the authorized user andenrolling those collected fingerprints in that database of knownfingerprint information.

It sometimes occurs that collecting fingerprints from the authorizeduser involves a user interface, in which the authorized user enters oneor more fingerprints, those fingerprints are processed if necessary toprovide fingerprint information, and that fingerprint information isenrolled in a database associated with that authorized user. Forexample, a user interface might request that the authorized user enterone or more fingerprints for each of their fingers, and might constructone or more data structures including fingerprint information, so thatnew fingerprints can be compared with the fingerprint informationenrolled in those data structures.

It sometimes occurs that the process of collecting fingerprints from theauthorized user, using that user interface, is time consuming. This canhave the effect that the authorized user finds the operation ofcollecting and enrolling fingerprints to be tedious, or otherwiseimpractical.

It sometimes occurs that the process of collecting fingerprints from theauthorized user, using that user interface, interrupts operations theauthorized user is attempting to perform. This can have the effect thatthe authorized user finds the operation of collecting and enrollingfingerprints to be a hindrance, or otherwise impractical.

Each of these examples, as well as other possible considerations, cancause difficulty for the authorized user in their interaction with thefingerprint recognition sensor, and in their interaction with the deviceincorporating the fingerprint recognition sensor (such as a computingdevice using fingerprint recognition for authentication). For example,as noted above, the authorized user might find a user interface forcollecting and enrolling fingerprints to be annoying or otherwiseimpractical, and might shy away from using that user interface. Thismight have the effect that the fingerprint recognition sensor remainsunused, or is used less effectively than otherwise possible.

SUMMARY

This application provides techniques, including circuits and designs,which can receive information with respect to fingerprint images, orportions thereof, and which can be incorporated into devices usingfingerprint recognition. This application also provides techniques,including devices which perform fingerprint recognition and methodswhich can be performed by those devices.

In one embodiment, techniques can include providing a fingerprintrecognition sensor in which one or more portions of each fingerprint canbe collected as they are identified, and those portions can be combinedinto a unified fingerprint template. The unified fingerprint templatecan be enrolled without a user interface, and automaticallycredentialed. For example, a fingerprint recognition sensor can receiveone or more portions of fingerprints, maintain those portions in memoryor storage, combine received portions when appropriate, enrollfingerprint information when portions are combined into a substantiallycomplete fingerprint, and automatically associate that fingerprintinformation with credentials for a user who has that fingerprint. Asdescribed herein, partial and enrolled fingerprints can be maintained inmemory or storage and manipulated by a computing device, in response toand interactively with a physical contact or proximity to one or more ofa user's fingerprints.

In one embodiment, techniques can include maintaining a partiallyunified fingerprint collected from portions thereof, matching furtherportions of fingerprints with that partially unified fingerprint,expanding that partially unified fingerprint, and identifying when thatpartially unified fingerprint is adequate for use as a substantiallycomplete fingerprint. For example, a fingerprint recognition sensor canmaintain one or more partially unified fingerprints, and combine thosepartially unified fingerprints with each other when appropriate.

In one embodiment, techniques can include maintaining a partiallyunified fingerprint collected from portions thereof, identifying furtherportions of fingerprints which might match with that partially unifiedfingerprint, tentatively matching those further portions, and rejectingtentative matches in response to new information. For a first example,that new information can include a result of testing the partiallyunified fingerprint using received fingerprint information. For a secondexample, that new information can include a measure of quality of thosefurther portions. For a third example, then new information can includea measure of quality of matching those further portions with thatpartially unified fingerprint.

While multiple embodiments are disclosed, including variations thereof,still other embodiments of the present disclosure will become apparentto those skilled in the art from the following detailed description,which shows and describes illustrative embodiments of the disclosure. Aswill be realized, the disclosure is capable of modifications in variousobvious aspects, all without departing from the spirit and scope of thepresent disclosure. Accordingly, the drawings and detailed descriptionare to be regarded as illustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the subject matter that is regarded as formingthe present disclosure, it is believed that the disclosure will bebetter understood from the following description taken in conjunctionwith the accompanying Figures, in which:

FIG. 1 shows a conceptual drawing of a fingerprint recognition sensorincluded in a portion of a device.

FIG. 2 shows a conceptual drawing of a set of individual fingerprintnodes being linked into a fingerprint mesh and enrolled as a fingerprinttemplate.

FIG. 3 shows a conceptual drawing of a set of individual fingerprintnodes being matched.

FIG. 4 shows a conceptual drawing of a fingerprint template beingtentatively expanded with additional individual fingerprint nodes.

FIG. 5 shows a conceptual drawing of communication between a touch I/Odevice and a computing system.

FIG. 6 shows a conceptual drawing of a system including a fingerprintrecognition device.

FIG. 7 is a flow chart illustrating an example method for generating adata set corresponding to a fingerprint through operations of anelectronic device.

DETAILED DESCRIPTION

This application provides techniques, including circuits and designs,which can receive information with respect to fingerprint images, orportions thereof, and which can be incorporated into devices usingfingerprint recognition. This application also provides techniques,including devices which perform fingerprint recognition and methodswhich can be performed by those devices. Embodiments described hereinmay be configured to operate with a variety of sensors, including stripor swipe sensors, array or other two-dimensional sensors, and the like.In one embodiment, techniques can include providing a fingerprintrecognition sensor in which one or more portions of each fingerprint canbe collected as they are identified, and those portions can be combinedinto a unified fingerprint template. In this way, collection andenrollment of fingerprints may be simplified for users.

Terminology

Terms and phrases used herein are intended to be exemplary, not limitingin any way. Some examples of terms and phrases used herein include thefollowing:

The text “node”, and variants thereof, generally refers to an individualportion of the fingerprint, or information representative thereof, suchas might be collected by a fingerprint recognition sensor. For example,a node can include a block of fingerprint data's received by thefingerprint recognition sensor, and can be maintained by the fingerprintrecognition sensor as described herein.

The text “mosaic”, and variants thereof, generally refers to a partiallyunified fingerprint, or information representative thereof, collectedfrom one or more nodes. For example, one or more mosaics can bemaintained by the fingerprint recognition sensor as described herein.

The text “template”, and variants thereof, generally refers to asubstantially complete fingerprint, or information representativethereof. For example, a template can be constructed from one or moremosaics, or a mosaic and one or more additional nodes. A template canalso be received in response to a user interface.

After reading this application, those skilled in the art would recognizethat these statements of terminology would be applicable to techniques,methods, physical elements, and systems (whether currently known orotherwise), including extensions thereof inferred or inferable by thoseskilled in the art after reading this application.

Fingerprint Sensor System

FIG. 5 shows a conceptual drawing of communication between a touch I/Odevice and a computing system.

Described embodiments may include touch I/O device 1001 that can receivetouch input for interacting with computing system 1003 via wired orwireless communication channel 1002. Touch I/O device 1001 may be usedto provide user input to computing system 1003 in lieu of or incombination with other input devices such as a keyboard, mouse, etc. Oneor more touch I/O devices 1001 may be used for providing user input tocomputing system 1003. Touch I/O device 1001 may be an integral part ofcomputing system 1003 (e.g., touch screen on a laptop) or may beseparate from computing system 1003.

For example, touch I/O device 1001 can interact with a user with theuser touching the touch I/O device 1001 with the user's finger (orotherwise bringing the user's finger near to the touch I/O device 1001),with the effect that the touch I/O device 1001 can receive fingerprintimage data, and optionally provide feedback to the user that thefingerprint image data was received.

Touch I/O device 1001 may include a touch sensitive panel which iswholly or partially transparent, semitransparent, non-transparent,opaque or any combination thereof. Touch I/O device 1001 may be embodiedas a touch screen, touch pad, a touch screen functioning as a touch pad(e.g., a touch screen replacing the touchpad of a laptop), a touchscreen or touchpad combined or incorporated with any other input device(e.g., a touch screen or touchpad disposed on a keyboard, a tabletcomputing device, a smart phone and the like) or any multi-dimensionalobject having a touch sensitive surface for receiving touch input.

In one example, touch I/O device 1001 embodied as a touch screen mayinclude a transparent and/or semitransparent touch sensitive panelpartially or wholly positioned over at least a portion of a display.According to this embodiment, touch I/O device 1001 functions to displaygraphical data transmitted from computing system 1003 (and/or anothersource) and also functions to receive user input. In other embodiments,touch I/O device 1001 may be embodied as an integrated touch screenwhere touch sensitive components/devices are integral with displaycomponents/devices. In still other embodiments a touch screen may beused as a supplemental or additional display screen for displayingsupplemental or the same graphical data as a primary display and toreceive touch input.

Touch I/O device 1001 may be configured to detect the location of one ormore touches or near touches on device 1001 based on capacitive,resistive, optical, acoustic, inductive, mechanical, chemicalmeasurements, or any phenomena that can be measured with respect to theoccurrences of the one or more touches or near touches in proximity todevice 1001. Software, hardware, firmware or any combination thereof maybe used to process the measurements of the detected touches to identifyand track one or more gestures or fingerprints. A gesture or fingerprintmay correspond to stationary or non-stationary, single or multiple,touches or near touches on touch I/O device 1001. A gesture orfingerprint may be performed by moving one or more fingers or otherobjects in a particular manner on touch I/O device 1001 such as tapping,pressing, rocking, scrubbing, twisting, changing orientation, pressingwith varying pressure and the like at essentially the same time,contiguously, or consecutively. A gesture or fingerprint may becharacterized by, but is not limited to a pinching, sliding, swiping,rotating, flexing, dragging, or tapping motion between or with any otherfinger or fingers. A single gesture may be performed with one or morehands, by one or more users, or any combination thereof.

Computing system 1003 may drive a display with graphical data to displaya graphical user interface (GUI). The GUI may be configured to receivetouch input via touch I/O device 1001. Embodied as a touch screen, touchI/O device 1001 may display the GUI. Alternatively, the GUI may bedisplayed on a display separate from touch I/O device 1001. The GUI mayinclude graphical elements displayed at particular locations within theinterface. Graphical elements may include but are not limited to avariety of displayed virtual input devices including virtual scrollwheels, a virtual keyboard, virtual knobs, virtual buttons, any virtualUI, and the like. A user may perform gestures at one or more particularlocations on touch I/O device 1001 which may be associated with thegraphical elements of the GUI. In other embodiments, the user mayperform gestures at one or more locations that are independent of thelocations of graphical elements of the GUI. Gestures performed on touchI/O device 1001 may directly or indirectly manipulate, control, modify,move, actuate, initiate or generally affect graphical elements such ascursors, icons, media files, lists, text, all or portions of images, orthe like within the GUI. For instance, in the case of a touch screen, auser may directly interact with a graphical element by performing agesture over the graphical element on the touch screen. Alternatively, atouch pad generally provides indirect interaction. Gestures may alsoaffect non-displayed GUI elements (e.g., causing user interfaces toappear) or may affect other actions within computing system 1003 (e.g.,affect a state or mode of a GUI, application, or operating system).Gestures may or may not be performed on touch I/O device 1001 inconjunction with a displayed cursor. For instance, in the case in whichgestures are performed on a touchpad, a cursor (or pointer) may bedisplayed on a display screen or touch screen and the cursor may becontrolled via touch input on the touchpad to interact with graphicalobjects on the display screen. In other embodiments in which gesturesare performed directly on a touch screen, a user may interact directlywith objects on the touch screen, with or without a cursor or pointerbeing displayed on the touch screen.

Feedback may be provided to the user via communication channel 1002 inresponse to or based on the touch or near touches on touch I/O device1001. Feedback may be transmitted optically, mechanically, electrically,olfactory, acoustically, or the like or any combination thereof and in avariable or non-variable manner. For example, feedback can includeinteraction with a user indicating (A) that one or more sets offingerprint image information have been received, (B) that one or moresets of fingerprint image information have been enrolled in a database,and possibly what credentials have been associated with those one ormore sets of fingerprint image information, (C) that one or more sets offingerprint image information have been confirmed as associated with theuser, or otherwise.

FIG. 6 shows a conceptual drawing of a system including a fingerprintrecognition device.

Attention is now directed towards embodiments of a system architecturethat may be embodied within any portable or non-portable deviceincluding but not limited to a communication device (e.g. mobile phone,smart phone), a multi-media device (e.g., MP3 player, TV, radio), aportable or handheld computer (e.g., tablet, netbook, laptop), a desktopcomputer, an All-In-One desktop, a peripheral device, or any othersystem or device adaptable to the inclusion of system architecture 2000,including combinations of two or more of these types of devices. A blockdiagram of one embodiment of system 2000 generally includes one or morecomputer-readable mediums 2001, processing system 2004, Input/Output(I/O) subsystem 2006, radio frequency (RF) circuitry 2008 and audiocircuitry 2010. These components may be coupled by one or morecommunication buses or signal lines 2003. Each such bus or signal linemay be denoted in the form 2003-X, where X is a unique number. The busor signal line may carry data of the appropriate type betweencomponents; each bus or signal line may differ from other buses/lines,but may perform generally similar operations.

It should be apparent that the architecture shown in the figure is onlyone example architecture of system 2000, and that system 2000 could havemore or fewer components than shown, or a different configuration ofcomponents. The various components shown in the figure can beimplemented in hardware, software, firmware or any combination thereof,including one or more signal processing and/or application specificintegrated circuits.

RF circuitry 2008 is used to send and receive information over awireless link or network to one or more other devices and includeswell-known circuitry for performing this function. RF circuitry 2008 andaudio circuitry 2010 are coupled to processing system 2004 viaperipherals interface 2016. Interface 2016 includes various knowncomponents for establishing and maintaining communication betweenperipherals and processing system 2004. Audio circuitry 2010 is coupledto audio speaker 2050 and microphone 2052 and includes known circuitryfor processing voice signals received from interface 2016 to enable auser to communicate in real-time with other users. In some embodiments,audio circuitry 2010 includes a headphone jack (not shown).

Peripherals interface 2016 couples the input and output peripherals ofthe system to processor 2018 and computer-readable medium 2001. One ormore processors 2018 communicate with one or more computer-readablemediums 2001 via controller 2020. Computer-readable medium 2001 can beany device or medium that can store code and/or data for use by one ormore processors 2018. Medium 2001 can include a memory hierarchy,including but not limited to cache, main memory and secondary memory.The memory hierarchy can be implemented using any combination of RAM(e.g., SRAM, DRAM, DDRAM), ROM, FLASH, magnetic and/or optical storagedevices, such as disk drives, magnetic tape, CDs (compact disks) andDVDs (digital video discs). Medium 2001 may also include a transmissionmedium for carrying information-bearing signals indicative of computerinstructions or data (with or without a carrier wave upon which thesignals are modulated). For example, the transmission medium may includea communications network, including but not limited to the Internet(also referred to as the World Wide Web), intranet(s), Local AreaNetworks (LANs), Wide Local Area Networks (WLANs), Storage Area Networks(SANs), Metropolitan Area Networks (MAN) and the like.

One or more processors 2018 run various software components stored inmedium 2001 to perform various functions for system 2000. In someembodiments, the software components include operating system 2022,communication module (or set of instructions) 2024, touch processingmodule (or set of instructions) 2026, graphics module (or set ofinstructions) 2028, one or more applications (or set of instructions)2030, and fingerprint sensing module (or set of instructions) 2038. Eachof these modules and above noted applications correspond to a set ofinstructions for performing one or more functions described above andthe methods described in this application (e.g., thecomputer-implemented methods and other information processing methodsdescribed herein). These modules (i.e., sets of instructions) need notbe implemented as separate software programs, procedures or modules, andthus various subsets of these modules may be combined or otherwiserearranged in various embodiments. In some embodiments, medium 2001 maystore a subset of the modules and data structures identified above.Furthermore, medium 2001 may store additional modules and datastructures not described above.

Operating system 2022 includes various procedures, sets of instructions,software components and/or drivers for controlling and managing generalsystem tasks (e.g., memory management, storage device control, powermanagement, etc.) and facilitates communication between various hardwareand software components.

Communication module 2024 facilitates communication with other devicesover one or more external ports 2036 or via RF circuitry 2008 andincludes various software components for handling data received from RFcircuitry 2008 and/or external port 2036.

Graphics module 2028 includes various known software components forrendering, animating and displaying graphical objects on a displaysurface. In embodiments in which touch I/O device 2012 is a touchsensitive display (e.g., touch screen), graphics module 2028 includescomponents for rendering, displaying, and animating objects on the touchsensitive display.

One or more applications 2030 can include any applications installed onsystem 2000, including without limitation, a browser, address book,contact list, email, instant messaging, word processing, keyboardemulation, widgets, JAVA-enabled applications, encryption, digitalrights management, voice recognition, voice replication, locationdetermination capability (such as that provided by the globalpositioning system (GPS)), a music player, etc.

Touch processing module 2026 includes various software components forperforming various tasks associated with touch I/O device 2012 includingbut not limited to receiving and processing touch input received fromI/O device 2012 via touch I/O device controller 2032.

System 2000 may further include fingerprint sensing module 2038 forperforming the method/functions as described herein in connection withFIGS. 1-4. Fingerprint sensing module 2038 may at least be executed to,or otherwise function to, perform various tasks associated with thefingerprint sensor, such as receiving and processing fingerprint sensorinput. The fingerprint sensing module 2038 may also control certainoperational aspects of the fingerprint sensor 2042, such as its captureof fingerprint data and/or transmission of the same to the processor2018 and/or secure processor 2040. Module 2038 may also interact withthe touch I/O device 2012, graphics module 2028 or other graphicaldisplay. Module 2038 may be embodied as hardware, software, firmware, orany combination thereof. Although module 2038 is shown to reside withinmedium 2001, all or portions of module 2038 may be embodied within othercomponents within system 2000 or may be wholly embodied as a separatecomponent within system 2000.

I/O subsystem 2006 is coupled to touch I/O device 2012 and one or moreother I/O devices 2014 for controlling or performing various functions.Touch I/O device 2012 communicates with processing system 2004 via touchI/O device controller 2032, which includes various components forprocessing user touch input (e.g., scanning hardware). One or more otherinput controllers 2034 receives/sends electrical signals from/to otherI/O devices 2014. Other I/O devices 2014 may include physical buttons,dials, slider switches, sticks, keyboards, touch pads, additionaldisplay screens, or any combination thereof. Such buttons may bephysical or virtual. The buttons may be soft. That is, the button orbuttons may be physically shown on a surface, but may not be associatedwith, or operate, a mechanical switch when pressed or otherwiseinteracted with.

If embodied as a touch screen, touch I/O device 2012 displays visualoutput to the user in a GUI. The visual output may include text,graphics, video, and any combination thereof. Some or all of the visualoutput may correspond to user-interface objects. Touch I/O device 2012forms a touch-sensitive surface that accepts touch input from the user.Touch I/O device 2012 and touch screen controller 2032 (along with anyassociated modules and/or sets of instructions in medium 2001) detectsand tracks touches or near touches (and any movement or release of thetouch) on touch I/O device 2012 and converts the detected touch inputinto interaction with graphical objects, such as one or moreuser-interface objects. In the case in which device 2012 is embodied asa touch screen, the user can directly interact with graphical objectsthat are displayed on the touch screen. Alternatively, in the case inwhich device 2012 is embodied as a touch device other than a touchscreen (e.g., a touch pad), the user may indirectly interact withgraphical objects that are displayed on a separate display screenembodied as I/O device 2014.

Touch I/O device 2012 may be analogous to the multi-touch sensitivesurface described in the following U.S. Pat. No. 6,323,846 (Westerman etal.), U.S. Pat. No. 6,570,557 (Westerman et al.), and/or U.S. Pat. No.6,677,932 (Westerman), and/or U.S. Patent Publication 2002/0015024A1,each of which is hereby incorporated by reference.

For embodiments in which touch I/O device 2012 is a touch screen, thetouch screen may use LCD (liquid crystal display) technology, LPD (lightemitting polymer display) technology, OLED (organic LED), or OEL(organic electro luminescence), although other display technologies maybe used in other embodiments.

Feedback may be provided by touch I/O device 2012 based on the user'stouch input as well as a state or states of what is being displayedand/or of the computing system. Feedback may be transmitted optically(e.g., light signal or displayed image), mechanically (e.g., hapticfeedback, touch feedback, force feedback, or the like), electrically(e.g., electrical stimulation), olfactory, acoustically (e.g., beep orthe like), or the like or any combination thereof and in a variable ornon-variable manner.

System 2000 also includes power system 2044 for powering the varioushardware components and may include a power management system, one ormore power sources, a recharging system, a power failure detectioncircuit, a power converter or inverter, a power status indicator and anyother components typically associated with the generation, managementand distribution of power in portable devices.

In some embodiments, peripherals interface 2016, one or more processors2018, and memory controller 2020 may be implemented on a single chip,such as processing system 2004. In some other embodiments, they may beimplemented on separate chips.

In addition to the foregoing, the system 2000 may include a secureprocessor 2040 in communication with a fingerprint sensor 2042, via afingerprint I/O controller 2044. Secure processor 2040 may beimplemented as one or more processing units. The operation of thesevarious elements will now be described.

The fingerprint sensor 2042 may operate to capacitively capture a seriesof images, or nodes. When taken together, these nodes may form a set offingerprint image information. A collection of nodes may be referred toherein as a “mesh”, “mosaic”, “template”, or other indicator offingerprint information. The fingerprint sensor may be located in anysuitable portion of the electronic device, such as beneath a display,under or along one or more walls of the device, beneath a buttonassociated with the device, and so on. Such buttons may be physical orvirtual. The buttons may be soft. That is, the button or buttons may bean icon or scribed into a surface of the electronic device, but may notphysically depress in the manner of a conventional button having arocker, slider or dome switch. Rather, operation of the button may beaccomplished by touching the soft button and sensing that touch. Thefingerprint sensor 2042 may be positioned beneath such a soft button incertain implementations. A “soft button” may refer to an input area orregion that does not substantially move, for example to depress a switchor mechanically create a contact, when touched or pressed.

Each node of fingerprint information may be separately captured by thefingerprint sensor 2042, which may be an array sensor. Generally, thereis some overlap between images in nodes representing adjacent portionsof a fingerprint. Such overlap may assist in assembling the fingerprintfrom the nodes, as various image recognition techniques may be employedto use the overlap to properly identify and/or align adjacent nodes inthe fingerprint information.

Sensed fingerprint data may be transmitted through the fingerprint I/Ocontroller 2044 to the processor 2018 and/or the secure processor 2040.In some embodiments, the data is relayed from the fingerprint I/Ocontroller 2044 to the secure processor 2040 directly. The fingerprintdata is encrypted, obfuscated, or otherwise prevented from beingaccessed by an unauthorized device or element, by any of the fingerprintsensor 2042, the fingerprint I/O controller 2044 or another elementprior to being transmitted to either processor. The secure processor2040 may decrypt the data to reconstruct the node. In some embodiments,unencrypted data may be transmitted directly to the secure processor2040 from the fingerprint controller 2044 (or the sensor 2042 if nocontroller is present). The secure processor may then encrypt this data.

Fingerprint data, either as individual nodes, collections of nodes, orsubstantially complete fingerprint templates, may be stored in thecomputer-readable medium 2001 and accessed as necessary. In someembodiments, only the secure processor 2040 may access storedfingerprint data, while in other embodiments either the secure processoror the processor 2018 may access such data.

Fingerprint Recognition Sensor

FIG. 1 shows a conceptual drawing of a fingerprint recognition sensorincluded in a portion of a device.

A device includes a fingerprint recognition sensor, capable of receivingfingerprint image data, such as from a fingerprint image sensor(optionally including the touch I/O device 2012 described herein) andincluding one or more processing units (such as the processor 2018 andthe secure processor 2040 described herein), maintaining a database offingerprint information, such as one or more enrolled templates, andcomparing received fingerprints with those enrolled templates. Thefingerprint recognition sensor can include a set of instructions whichcan be interpreted or executed by a processor. The fingerprintrecognition sensor can include, or have access to, memory or storage inwhich it can maintain and manipulate fingerprint information, such asone or more databases of fingerprint information which can be used tomanipulate and compare fingerprint information, as described herein

In one embodiment, each database of fingerprint information can includea set of fingerprint image data, which can include a set of fingerprintimage nodes, such as responsive to the touch I/O device 2012 describedherein. For example, each set of fingerprint image nodes can include an8×8 block of image fingerprint image data received from the operation ofthe fingerprint recognition sensor, and maintained in memory or storageincluded with or accessible to the processing unit. Each database offingerprint information can include a set of fingerprint image mosaicsand templates, determined by the processing unit in response to thefingerprint image nodes, and similarly maintained in memory or storageincluded with or accessible to the processing unit.

The fingerprint recognition sensor can receive fingerprints associatedwith an authorized user, determine a template in response to thosereceived fingerprints, and enroll that template in that database offingerprint information. The fingerprint recognition sensor can receivenew fingerprints, match those new fingerprints with those enrolledtemplates, and determine if those new fingerprints are also associatedwith that authorized user, and if so, what credentials are associatedwith that enrolled template. The fingerprint sensor may receive orcapture fingerprint image nodes during a user's operation of a device.For example, nodes may be captured as a use presses a button orinteracts with a surface (such as a touch screen) overlaying thefingerprint sensor, even if the interaction is not an attempt to enrolla user. Continuing the example, the fingerprint sensor may capture nodeswhile a user plays a game on the electronic device, places a telephonecall, or otherwise provides input to the electronic device. Such nodesmay be fragmentary portions of a fingerprint and an entire fingerprintmay not be captured during a single user session. Accordingly, the nodesmay be stored in a database for later processing in order to create aunified image of a fingerprint, which may then be enrolled with thedevice or otherwise registered by the device to provide authorization oraccess to particular functions.

The fingerprint recognition sensor also includes a database ofnon-enrolled fingerprint information, such as one or more nodes, andsuch as one or more mosaics. The fingerprint recognition sensor canreceive one or more nodes, maintain a database of node information, andmaintain a database of mosaic information.

The fingerprint recognition sensor can match first nodes and mosaicswith second nodes and mosaics, and determine whether to combine thosefirst nodes and mosaics with those second nodes and mosaics. Thefingerprint recognition sensor can determine, for each mosaic, whetherthat mosaic is sufficiently complete to be enrolled as a template.

Linking Individual Nodes

FIG. 2 shows a conceptual drawing of a set of individual fingerprintnodes being linked into a fingerprint mosaic and enrolled as afingerprint template. As described herein, processed fingerprint imagedata, including individual nodes, mosaics, can be maintained in memoryor storage and manipulated by a computing device, in response to andinteractively with a physical contact or proximity to one or more of auser's fingerprints.

A database of non-enrolled fingerprint information can include one ormore individual nodes. In one embodiment, each time a user touches (orhas their fingerprint otherwise sensed by) the fingerprint recognitionsensor, if the fingerprint recognition sensor is unable to recognize anentire fingerprint for comparison, the fingerprint recognition sensorcan instead identify one or more nodes. For example, each node caninclude a block of fingerprint data's, which can be processed todetermine fingerprint information about that node. Fingerprintinformation about that node can include a set of ridge flow information,a set of edge matching information, or other information from which thefingerprint recognition sensor can determine whether that node caneventually be combined with any other node into a unified fingerprinttemplate.

In one embodiment, the fingerprint recognition sensor maintains a recordof a set of nodes, and maintains a record of a set of mosaics, whereeach mosaic includes a collection of nodes which the fingerprintrecognition sensor has determined should be included in a unifiedtemplate. For a first example, if a first node and a second node matchwell along an edge, the fingerprint recognition sensor can collect thosenodes into a mosaic. For a second example, if a node matches well withany of the nodes in the mosaic, the fingerprint recognition sensor cancollect that node with that mosaic and expand the mosaic to a largermosaic. For a third example, if a first mosaic and a second mosaicinclude nodes which match well, the fingerprint recognition sensor cancollect those mosaics into a larger mosaic which includes the nodes fromboth of them. For a fourth example, if a node matches well with any ofthe nodes in both the first mosaic and the second mosaic, thefingerprint recognition sensor can collect those mosaics into a largermosaic which includes the nodes from both of them, as well as the newnode which matched both mosaics. This has the effect that, as nodes arediscovered which match, they are collected into mosaics, the mosaicsgrow in size, and the mosaics can be collected into larger mosaics.

In one embodiment, the fingerprint recognition sensor can determine ifand when a mosaic has sufficient information to comprise a completetemplate, so that the mosaic can be enrolled as a new template. If so,the fingerprint recognition sensor can enroll the mosaic as a newtemplate, associate that template with a user, and associate thattemplate with appropriate credentials, such as those credentialsafforded to that user. This has the effect that a new template can becollected from individual nodes, without an authorized user interactingwith a user interface to enroll that new template.

In one embodiment, the fingerprint recognition sensor can make thedetermination of whether the mosaic should be enrolled as a new templatein response to one or more factors. For a first example, the mosaic canbe enrolled in response to a number of nodes it includes. In particular,when a mosaic includes 9 or more nodes, it can be declared sufficientlycomplete to be enrolled as a template. For a second example, the mosaiccan be enrolled in response to a diameter of a region it covers. Inparticular, when a mosaic has a diameter of 4 or more nodes in Euclideandistance (or 6 or more nodes in Manhattan distance), it can be declaredsufficiently complete to be enrolled as a template. For a third example,the mosaic can be enrolled in response to a degree of confidence thatthe fingerprint recognition sensor has with respect to whether themosaic can be used to match fingerprints for authorization.

In one embodiment, templates that are collected from mosaics, andultimately from individual nodes, are assigned a relatively lesserimportance than templates that are collected by the authorized userinteracting with a user interface to enroll that new template. Templatesthat are collected from mosaics can be removed if they fail to match anywhole fingerprints when the fingerprint recognition sensor attempts toauthorize a user. For a first example, if a template collected frommosaics is not usable for some time duration or for some number ofattempts (or some other measure of inaccuracy or lack of usefulness),that template can be de-enrolled. For a second example, that templatecan be demoted to a mosaic and possibly altered to improve its utility,as described below.

Matching Nodes With A Mosaic

FIG. 3 shows a conceptual drawing of a set of individual fingerprintnodes being matched.

In one embodiment, the fingerprint recognition sensor matches nodes bydetermining whether they are sufficiently alike in an overlappingregion. For a first example, if nodes each include an 8×8 block of datacaptured by fingerprint data's, the fingerprint recognition sensor canassert that a first node matches a second node if a sufficient number ofdata points in a 2×8 overlapping stripe are identical or nearlyidentical, for example when adjusted for gain of the fingerprint data's.For a second example, the fingerprint recognition sensor can assert thata first node matches a second node if there is a match between the firstand second nodes for one or more of: a ridge flow, a ridge flowgradient, or another set of fingerprint information derived fromfingerprint image fingerprint data's.

In one embodiment, when a first node and a second node match well alonga designated edge, the fingerprint recognition sensor need not look tothat designated edge for further matching new nodes. In alternativeembodiments, the fingerprint recognition sensor can downgrade thatdesignated edge when searching its database of nodes and mosaics formatching a new node. For example, the fingerprint recognition sensor canassign a priority to searching for a new match at the designated edge,such as a priority which is lower when the match along the designatededge is better.

In one embodiment, the fingerprint recognition sensor determines howmany matches there are between common edges of a first mosaic and asecond mosaic. For a first example, if there is only a single suchmatch, the fingerprint recognition sensor can collect those mosaics onlytentatively, while if there is more than one such match, the fingerprintrecognition sensor can collect those mosaics more definitively. For asecond example, the fingerprint recognition sensor can assign a measureof confidence to collecting those mosaics, in response to how manymatches there are at designed edges of those mosaics (and whethermatches at those designed edges are physically feasible).

More generally, the fingerprint recognition sensor can assign a measureof confidence to each match it determines, with the effect that eachtime the fingerprint recognition sensor collects a first node with asecond node, or a node with a mosaic, or a first mosaic with a secondmosaic, it can recompute that measure of confidence with respect towhether the collection is reasonable. For a first example, thefingerprint recognition sensor can increase its confidence forcollecting nodes or mosaics if there are multiple independent reasons todo so. For a second example, the fingerprint recognition sensor canmaintain a record of which attempts to collect nodes and mosaics arerelatively higher confidence, with the effect that if the fingerprintrecognition sensor needs to revert its attempt to collect nodes ormosaics, it can start at the least-confident joining place.

One case in which the fingerprint recognition sensor might desire torevert its attempt to collect nodes or mosaics can occur when nodes arecollected from more than one user, and which can be matched, eitherbecause matching is performed relatively aggressively or because thosenodes match by coincidence. Fingerprints are generally believed to beunique to individuals, but it is possible that a portion of afingerprint from one person might match a portion of a fingerprint fromanother person. In such cases, the fingerprint recognition sensor wouldfind that the collected mosaic, or an enrolled template derived fromthat mosaic, would not match a fingerprint from either single user, withthe effect that the fingerprint recognition sensor would desire toeither discard that template, or to revert the join of those nodes ormosaics.

In one embodiment, the fingerprint recognition sensor can use otherinformation about a node to determine its measure of confidence inwhether to connect that node with another node or with a mosaic. For afirst example, if the node to be joined includes relatively less entropyor relatively less information, the fingerprint recognition sensor canassign that node, and any attempt to join that node, less confidence.For a second example, the fingerprint recognition sensor can compute itsmeasure of confidence in response to the amount of entropy orinformation in that node, or in the edge where that node is to bejoined.

More generally, the information which the fingerprint recognition sensoruses to determine its measure of confidence can include any informationit has available about the node, such as (A) how long ago the node wascollected, (B) how long the node has gone without any matches, or sinceits most recent match, (C) how far away the node is from the largestmosaic, or the nearest mosaic exceeding a threshold size, (D) whethertwo nodes to be matched have similar entropy, or similar amounts ofinformation, or otherwise.

The fingerprint recognition sensor can also use information with respectto its confidence in a node to determine whether it should remove thenode entirely. For example, if a node was collected a relatively longtime ago, has not ever matched any other node, and has relatively lowentropy, the fingerprint recognition sensor can determine that the nodedoes not have sufficient value to retain it.

The fingerprint recognition sensor can also use information with respectto its confidence in a node to determine in what order to search nodesto see if any match with a newly acquired node or with a recentlyconstructed mosaic. For example, if a node is relatively recent, thefingerprint recognition sensor can assign it a relatively higherpriority when searching for matching nodes. Similarly, if a mosaic wascreated relatively recently, the fingerprint recognition sensor canassign it a relatively higher priority when searching for matching nodesto expand that mosaic.

Expanding A Template

FIG. 4 shows a conceptual drawing of a fingerprint template beingtentatively expanded with additional individual fingerprint nodes. Asdescribed herein, the nodes, mosaics, and templates derived from afingerprint image can be maintained in memory or storage and manipulatedby a computing device, in response to and interactively with a physicalcontact or proximity to one or more of a user's fingerprints.

In one embodiment, when the fingerprint recognition sensor determinesthat a mosaic is sufficiently complete to be enrolled as a template, itmight occur that the fingerprint recognition sensor later findsadditional information that can be added to that template. For a firstexample, as noted above, the fingerprint recognition sensor mightdetermine that the template fails to match any actual user fingerprint,and must be discarded or alternatively, disjoined at some place. For asecond example, the fingerprint recognition sensor might receive one ormore additional nodes or identify one or more mosaics that can be joinedwith the template.

In one embodiment, the fingerprint recognition sensor can attempt tomodify the enrolled template. For a first example, the fingerprintrecognition sensor might modify the enrolled template directly. For asecond example, the fingerprint recognition sensor might maintain theenrolled template as a mosaic in its database of non-enrolledfingerprint information, marking that mosaic as corresponding to anenrolled template and retaining the option to modify the mosaic andpossibly re-enroll it.

In one embodiment, the fingerprint recognition sensor can follow thesecond described example. When a template is identified that thefingerprint recognition sensor desires to modify, the fingerprintrecognition sensor can de-enroll that template, mark the associatedmosaic as no longer enrolled, modify the associated mosaic, andre-enroll the modified associated mosaic.

For a first example, if the enrolled template fails to match any actualuser fingerprint, it might be the case that the fingerprint recognitionsensor has mistakenly joined nodes from more than one fingerprint. Thismight occur because an individual user has more than one finger withnodes that matched well, or this might occur because more than one userhave nodes that matched well. In either case, the fingerprintrecognition sensor discards the enrolled template, marks the associatedmosaic as no longer enrolled, marks the associated mosaic as erroneous,and takes appropriate action.

Appropriate action can include (A) deleting the associated mosaicentirely, or (B) de-joining one or more nodes or mosaics from theassociated mosaic. As noted above, if the fingerprint recognition sensorhas maintained a record of its confidence in each joining location, thefingerprint recognition sensor can de-join the associated mosaic at theleast-confident location (or alternatively, at a relatively lessconfident location which is otherwise convenient), and mark thede-joined location as not to be re-joined without better evidence infavor thereof.

For a second example, if the enrolled template can be expanded withadditional nodes, either by joining it with one or more individual nodesor by joining it with one or more additional mosaics, the fingerprintrecognition sensor can join the associated mosaic with that additionalinformation, determine if the revised mosaic should be re-enrolled as atemplate, and if so, re-enroll the expanded mosaic as an expandedtemplate. In one embodiment, the fingerprint recognition sensor canmaintain both the smaller and the larger template as enrolled templates,including metadata to note that both the smaller and the larger templateoverlap. This has the effect that if the larger template proves to besuperior, the smaller template can be de-enrolled and removed. On theother hand, if the larger template proves to be unworkable (such as, asnoted above, if two fingerprints are mistakenly conflated), the smallertemplate can be retained, and the larger template can be de-enrolled andremoved.

Automatic Enrollment

In one embodiment, when a fingerprint template is recognized andenrolled, the fingerprint recognition sensor can automaticallycredential that fingerprint template, either as part of the enrollmentprocess, as part of a process performed after enrollment, or as part ofan ongoing automated credentialing process. As previously mentioned,various nodes may be captured during normal operation of an electronicdevice incorporating or associated with the fingerprint recognitionsensor. These nodes may be stored and, over time, accumulated into amosaic and ultimately a template. The capture of nodes and relatedfingerprint data may occur without the user's knowledge, while the userotherwise interacts with the electronic device. For a first example,upon enrollment of a fingerprint template, the fingerprint recognitionsensor can determine a user associated with that fingerprint template,and automatically associated credentials with that fingerprint templatethat are already associated with that user. For a second example, uponany update or re-enrollment of that fingerprint template, such asdescribed above, the fingerprint recognition sensor can automaticallyupdate the credentials associated with that fingerprint template. For athird example, upon any update of the credentials for a user associatedwith that fingerprint template, the fingerprint recognition sensor canautomatically update the credentials associated with that fingerprinttemplate to match the credentials for that associated user.

In one embodiment, when a fingerprint template is recognized andenrolled, the fingerprint recognition sensor can automatically notifythe user, or take some other selected action. For a first example, thefingerprint recognition sensor can automatically notify the user whenthe fingerprint template is recognized and enrolled. As part of thisnotification, the fingerprint recognition sensor can take otherappropriate action, such as possibly (A) asking the user to confirmenrollment, (B) asking the user to confirm credentials to be associatedwith the fingerprint template, (C) asking the user to enter a PIN orother code to confirm they are the correct user. For a second example,the fingerprint recognition sensor can automatically take some otherselected action, such as a system action, such as maintaining a recordof enrolled fingerprints and the time and place they were enrolled.

FIG. 7 is a flow chart illustrating a method 700 for generating a dataset corresponding to a fingerprint through operations of an electronicdevice. The electronic device may be the device of FIG. 1. The methodmay start at a block 701 and the flow may proceed to block 702 where afirst node and a second node may be captured, such as by a fingerprintsensor of the electronic device. The flow may then proceed to block 703where the first node is matched to the second node. The flow may thenproceed to block 704 where a relative position of the first node and thesecond node is determined. Next, the flow may proceed to block 705 wherethe first node and the second node, and the relative position of thefirst node and second node, are stored as a mosaic. In some cases,capture of one or more of the first node and second node may beperformed by a fingerprint sensor during an interaction with anelectronic device other than a dedicated enrollment action.

As described above and illustrated in the accompanying drawings, thisapplication provides techniques, including circuits and designs, whichcan receive information with respect to fingerprint images, or portionsthereof, and which can be incorporated into devices using fingerprintrecognition. This application also provides techniques, includingdevices which perform fingerprint recognition and methods which can beperformed by those devices. In one embodiment, techniques can includeproviding a fingerprint recognition sensor in which one or more portionsof each fingerprint can be collected as they are identified, and thoseportions can be combined into a unified fingerprint template. In thisway, collection and enrollment of fingerprints may be simplified forusers.

Certain aspects of the embodiments described in the present disclosuremay be provided as a computer program product, or software, that mayinclude, for example, a computer-readable storage medium or anon-transitory machine-readable medium having stored thereoninstructions, which may be used to program a computer system (or otherelectronic devices) to perform a process according to the presentdisclosure. A non-transitory machine-readable medium includes anymechanism for storing information in a form (e.g., software, processingapplication) readable by a machine (e.g., a computer). Thenon-transitory machine-readable medium may take the form of, but is notlimited to, a magnetic storage medium (e.g., floppy diskette, videocassette, and so on); optical storage medium (e.g., CD-ROM);magneto-optical storage medium; read only memory (ROM); random accessmemory (RAM); erasable programmable memory (e.g., EPROM and EEPROM);flash memory; and so on.

While the present disclosure has been described with reference tovarious embodiments, it will be understood that these embodiments areillustrative and that the scope of the disclosure is not limited tothem. Many variations, modifications, additions, and improvements arepossible. More generally, embodiments in accordance with the presentdisclosure have been described in the context of particular embodiments.Functionality may be separated or combined in procedures differently invarious embodiments of the disclosure or described with differentterminology. These and other variations, modifications, additions, andimprovements may fall within the scope of the disclosure as defined inthe claims that follow.

The present disclosure recognizes that personal information data,including biometric data, in the present technology, can be used to thebenefit of users. For example, the use of biometric authentication datacan be used for convenient access to device features without the use ofpasswords. In other examples, user biometric data is collected forproviding users with feedback about their health or fitness levels.Further, other uses for personal information data, including biometricdata, that benefit the user are also contemplated by the presentdisclosure.

The present disclosure further contemplates that the entitiesresponsible for the collection, analysis, disclosure, transfer, storage,or other use of such personal information data will comply withwell-established privacy policies and/or privacy practices. Inparticular, such entities should implement and consistently use privacypolicies and practices that are generally recognized as meeting orexceeding industry or governmental requirements for maintaining personalinformation data private and secure, including the use of dataencryption and security methods that meets or exceeds industry orgovernment standards. For example, personal information from usersshould be collected for legitimate and reasonable uses of the entity andnot shared or sold outside of those legitimate uses. Further, suchcollection should occur only after receiving the informed consent of theusers. Additionally, such entities would take any needed steps forsafeguarding and securing access to such personal information data andensuring that others with access to the personal information data adhereto their privacy policies and procedures. Further, such entities cansubject themselves to evaluation by third parties to certify theiradherence to widely accepted privacy policies and practices.

Despite the foregoing, the present disclosure also contemplatesembodiments in which users selectively block the use of, or access to,personal information data, including biometric data. That is, thepresent disclosure contemplates that hardware and/or software elementscan be provided to prevent or block access to such personal informationdata. For example, in the case of biometric authentication methods, thepresent technology can be configured to allow users to optionally bypassbiometric authentication steps by providing secure information such aspasswords, personal identification numbers (PINS), touch gestures, orother authentication methods, alone or in combination, known to those ofskill in the art. In another example, users can select to remove,disable, or restrict access to certain health-related applicationscollecting users' personal health or fitness data.

What is claimed is:
 1. An electronic device, comprising: a fingerprintsensor; a first processing element operatively connected to thefingerprint sensor; a first database operatively connected to the firstprocessing element, the first database storing a set of datacorresponding to non-enrolled fragments of one or more fingerprintscaptured by the fingerprint sensor during an interaction with thefingerprint sensor; and a second database operatively connected to thefirst processing element, the second database storing one or moreenrolled templates; wherein the first processing element is operativeto: determine when a plurality of the non-enrolled fragments match alongat least one edge; combine the plurality of the non-enrolled fragmentsthat match along the at least one edge to form a template; maintain oneor more non-enrolled fragments that do not match along at least one edgein the first database; and store the template in the second database,the stored template comprising an enrolled template.
 2. The electronicdevice of claim 1, wherein the first processing element is furtheroperative to remove the plurality of the non-enrolled fragments thatmatch along the at least one edge from the first database once thetemplate is formed.
 3. The electronic device of claim 2, furthercomprising a second processing element operatively connected to thefirst processing element; wherein the first processing element is secureand interacts only with the second processing element, the first and thesecond databases, and the fingerprint sensor.
 4. The electronic deviceof claim 3, wherein the second processing element is operativelyconnected to at least one output device.
 5. The electronic device ofclaim 4, wherein the at least one output device comprises atouch-sensitive display.
 6. The electronic device of claim 4, whereinthe first processing element generates the first set of data bydecrypting encrypted information transmitted from the fingerprintsensor, the encrypted information relating to fragments of one or morefingerprints.
 7. The electronic device of claim 1, wherein the firstdatabase is operative to store one or more mosaics, each of the one ormore mosaics being formed from a plurality of the non-enrolledfragments, wherein each of the one or more mosaics is less than a dataset corresponding to a portion of a fingerprint sufficient to identify aperson.
 8. The electronic device of claim 7, wherein the plurality ofthe non-enrolled fragments comprises a first non-enrolled fragment and asecond non-enrolled fragment and the first processing element isoperative to determine an edge overlap between the first and the secondnon-enrolled fragments and, in response thereto, generate a mosaic fromthe first and the second non-enrolled fragments.
 9. The electronicdevice of claim 1, wherein each of the fragments is captured during aninteraction with the electronic device other than a dedicated enrollmentinteraction.
 10. The electronic device of claim 9, wherein: the set oftemplates are separated into a first template group and a secondtemplate group; wherein the first template group contains only templatesformed from a series of fragments obtained during a dedicated enrollmentinteraction; and the second template group contains templates formedfrom a series of fragments, at least one of the series of fragmentsforming each template obtained during an interaction with the electronicdevice other than a dedicated enrollment action.
 11. The electronicdevice of claim 10, wherein the processor is operative to remove atemplate of the second template group if the template of the secondtemplate group does not match a fingerprint obtained during a series ofdedicated enrollment actions.
 12. A method for generating a templatecorresponding to a fingerprint through operations of an electronicdevice, the method comprising: storing, in a database of non-enrolledpartial fingerprints, a first node, a second node, and a third node or afirst mosaic; matching an edge of the first node to an edge of thesecond node; combining the first node and the second node into a secondmosaic and storing the second mosaic in the database of non-enrolledpartial fingerprints; combining the second mosaic and the third node orthe first mosaic into a larger third mosaic when an edge of the secondmosaic matches an edge of the first mosaic or the third node; andstoring the third mosaic as the template in a database of enrolledtemplates if the third mosaic comprises a complete template; and storingthe third mosaic in the database of non-enrolled partial fingerprints ifthe third mosaic does not comprise the complete template.
 13. The methodof claim 12, wherein the operation of matching the first node to thesecond node comprises: comparing data adjacent an edge of the first nodeto data adjacent an edge of the second node; and in the event the datais sufficiently similar, matching the edge of the first node to the edgeof the second node.
 14. The method of claim 13, wherein the data ischosen from the group comprising: ridge flow data; ridge flow gradientdata; and capacitively-sensed fingerprint data.
 15. The method of claim13, further comprising: downgrading the edge of the first node inpriority for later matching operations; and downgrading the edge of thesecond node in priority for later matching operations.
 16. The method ofclaim 13, further comprising: adjusting a confidence of a match based onat least one of: an age of the first node; a duration of time since thefirst node was last match; a distance of the first node from a largestmosaic; and an entropy of the first node.
 17. The method of claim 13,further comprising: determining a confidence of the first node; and inthe event the confidence of the first node is low, discarding the firstnode; wherein the operation of comparing data adjacent an edge of thefirst node to data adjacent an edge of the second node occurs only ifthe first node has not been discarded.
 18. An electronic device,comprising: a processor; and a memory coupled to the processor, thememory for storing instructions which, when executed by the processor,performs a method for reconstructing an image of a fingerprint, themethod comprising: capturing a first portion of a fingerprint during afirst non-enrollment interaction with the electronic device; capturing asecond portion of the fingerprint during a second non-enrollmentinteraction with the electronic device; storing the first and the secondportions of the fingerprint in a first database comprising non-enrolledportions of the fingerprint; comparing an edge of the first portion toan edge of the second portion; creating a fingerprint template using thefirst portion and the second portion when the comparison exceeds aconfidence match threshold; and storing the fingerprint template in asecond database comprising one or more enrolled templates.
 19. Theelectronic device of claim 18, wherein the method further comprises:capturing a third portion of the fingerprint during the secondnon-enrollment interaction with the electronic device; storing the thirdportion of the fingerprint in the first database comprising non-enrolledportions of the fingerprint; and continuing to store the third portionin the first database upon storing the fingerprint template in thesecond database.
 20. The electronic device of claim 18, wherein themethod further comprises removing the first and second portions from thefirst database once the template is created.